A wide variety of moisturizing lotions (“moisturizers”) are available to consumers. Many of these moisturizers are emulsions that contain relatively high levels of lipophilic materials, such as oils, emollients, lipophilic emulsifiers and/or fatty polyols. Moisturizers containing such ingredients may have a tacky feel, and/or poor “rub-in” properties, i.e., the moisturizer will tend to leave a noticeable residue or film on the skin surface, rather than being readily absorbed.
Attempts to improve the skin-feel and rub-in properties of such emulsions have generally focused on reducing the particle size of the droplets in the emulsion, e.g., by forming micro- or nano-emulsions. Micro-emulsions typically require relatively large amounts of emulsifiers and/or surfactants to provide emulsion stability—ingredients which may potentially cause skin irritation—while formation of nano-emulsions may require high shear or phase inversion temperature processing, which may limit the range of ingredients that can be included in the moisturizer.
Some cosmetic formulations include phospholipids to provide a combination of moisturizing properties and good aesthetic properties, e.g., skin-feel and rub-in. While phospholipids provide a good balance of properties, they are generally relatively expensive, and may pose shelf stability issues under some storage conditions.